PCBs in the Alaskan Environment
According to recent media accounts PCB is the latest chemical insult to the Alaskan environment. PCB (shorthand for "polychlorinated biphenyls") is not a single chemical but a complex mixture of substances produced from petro-chemicals and chlorine gas. The PCBs are chemically stable, and this property enhances their utility as heat exchange fluids, fire retardants, and plasticizers.
Chemically and biologically, PCBs are similar to DDT. Both are inert chlorinated hydrocarbons which persist in the environment, concentrate in most organisms (including man), and exhibit toxicity. The biological effects of PCBs are sufficient to raise concern. They allegedly contribute to reproductive failure, induce mutations, and cause chloracne (a severe skin disorder).
What will happen to the PCBs which have been introduced to the Alaskan environment? Recent research at the University of Alaska has shown that the waters of Port Valdez contain microorganisms which convert PCBs to harmless substances. However, they do so very slowly. The most reactive of the PCB components will reside unchanged in Port Valdez for five to ten years, and the more stable components are expected to remain intact up to ten times that long.
What can we learn from this unpleasant situation? Unlike DDT--which man has willfully distributed throughout the environment--the major uses of PCBs have been in localized, physically contained situations. They enter the environment primarily through man's carelessness. Undoubtedly a portion of Alaskan PCBs are "gifts" from our more industrialized neighbors. Airborne PCBs, primarily from refuse burning, are transported by wind to the Arctic. However, the high PCB levels found near Delta, Alaska, for example, must have come from a more highly concentrated source. The problem then resides with all of us and our "throw-away society." If we learn the proper handling of noxious substances from the Alaskan PCB episode, then perhaps the present problem will be beneficial. If, however, we ignore the question of how PCSs appeared at Delta, PCBs could well become a continuing serious problem.
